Suzuki GP100 restoration

shadowbiker · Traffic Copper Joined: 14 Oct 2009 Karma :

Ive recently acciered a suzuki gp100 with no v5 docs no history the frame numbers and keys are there, Its also HPI clear so ive sent off for the v5 document.

But needing some ideas on the restore as its been sat in a garden for years.

I belive its a 1972 model ive had a good look around the bike and have a small list of things i need to fix/get

seat, chain, brakes, spark plug, and a service ( to get it running )

new loom , side pannels, fork seals , battery and thats it i think

im thinking about ratting it ( as dunc told me too ) Laughing

anyone have any tips on how to go about the tasks any help on anything else that i should be aware of ?

heres some photos

https://i391.photobucket.com/albums/oo360/tonymini145/SP_A0410.jpg

https://i391.photobucket.com/albums/oo360/tonymini145/SP_A0411.jpg
https://i391.photobucket.com/albums/oo360/tonymini145/SP_A0412.jpg
https://i391.photobucket.com/albums/oo360/tonymini145/SP_A0413.jpg
https://i391.photobucket.com/albums/oo360/tonymini145/SP_A0414.jpg
https://i391.photobucket.com/albums/oo360/tonymini145/SP_A0415.jpg

27cows · World Chat Champion Joined: 01 Nov 2009 Karma :

That model has points, as I recall, so be careful. Loads of people holed the pistons of GP100s and 125s.

That'll be a 1982 model, not 72 Wink

I take it that was a typo.

Pretty good bikes, those that haven't rusted away. My mate tuned the buggery out of one and had it doing an indicated 90. I rode it once and it felt like it was doing about 200, but was probably nearer a real 80 Cool

shadowbiker · Traffic Copper Joined: 14 Oct 2009 Karma :

Billing · World Chat Champion Joined: 12 Mar 2009 Karma :

are you sure the fuel is getting to the cylinder? no blocked jets or sticky float? sometimes spark plugs fail, my TZR is an arse for killing plugs, they spark, but arent strong enough to ignite the fuel in the cylinder. for £3 its worth a shot.

replace the plug, try starting it, then take the plug out and see if its oily/wet. if not check the carb is clean Smile

make sure the air filter isnt blocked, itll run rich if it is

£14 for a new ignition barrel
https://cgi.ebay.co.uk/SUZUKI-GP100-GP-100-IGNITION-SWITCH-NEW-737548_W0QQitemZ400012872868QQcmdZViewItemQQptZUK_Motorcycle_Parts?hash=item5d22a00ca4
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shadowbiker · Traffic Copper Joined: 14 Oct 2009 Karma :

chris-red · Have you considered a TDM? Joined: 21 Sep 2005 Karma :

What do you mean you need new brakes? do you mean shoes?
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shadowbiker · Traffic Copper Joined: 14 Oct 2009 Karma :

27cows · World Chat Champion Joined: 01 Nov 2009 Karma :

shadowbiker · Traffic Copper Joined: 14 Oct 2009 Karma :

Billing · World Chat Champion Joined: 12 Mar 2009 Karma :

usually its under the seat, looks like yours may have been removed and made to run premix.

have a gander on ebay, should be a 2t tank on there, aswell as an airbox which also appears to be missing
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'84 TS50X, '91 TZR125, '89 CBR400RR, '91 VFR400R NC30, '98 R1
"Hey copernicus! Why don't you navigate yourself to the back of the line with your feet and stand there with your shit."
BCF Eastern members map here ---> g.co/maps/2tm8b PM me to be added to it!

shadowbiker · Traffic Copper Joined: 14 Oct 2009 Karma :

Billing · World Chat Champion Joined: 12 Mar 2009 Karma :

if you have the airbox, mount that first, if nothing it'll help with the running of the bike, because it won't be running lean. It also gives you less space where the 2t tank can fit, thereby narrowing your choice of positioning Wink

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'84 TS50X, '91 TZR125, '89 CBR400RR, '91 VFR400R NC30, '98 R1
"Hey copernicus! Why don't you navigate yourself to the back of the line with your feet and stand there with your shit."
BCF Eastern members map here ---> g.co/maps/2tm8b PM me to be added to it!

27cows · World Chat Champion Joined: 01 Nov 2009 Karma :

Think the oil bottle goes under the left panel.

shadowbiker · Traffic Copper Joined: 14 Oct 2009 Karma :

shadowbiker · Traffic Copper Joined: 14 Oct 2009 Karma :

Now got the reg docs in my name, so now i can really gut it

defo needs a new loom
good service and rebuild with a 180cc kit and 34mm carb and spoketed
ignition barrel
lick of paint
a good clean
deseize brakes
MOT and Tax
then insurance

hows that sound ? anything im missing/should be checking ?

Billing · World Chat Champion Joined: 12 Mar 2009 Karma :

i assume you haven't got your licence yet? so for a start you'll be riding WAY outside your legal limit. my second concer is that the bore kit you speak of is nearly twice the size of the original, this in itself encounters 2 major problems from the off

1) the bottom end is designed to take 100cc, maybe a bit over to be on the safe side. nearly doubling the capacity of the engine will probably kill it in no time (if it can be done, which brings me to problem 2)

2) even boring the cylinder to the max it'll never get to almost twice the diameter. maybe a few mil to gain a little bit more capacity. so by this logic, you'll need to get the stroke changed, which i think is achieved by altering the crankshaft throw, meaning you may need to alter the crank cases to accomodate this.

from what I've gathered the standard size piston is 50mm, which means you will need to bore it roughly 40mm if your only going to bore it Shocked

but apart from this your plan is solid Thumbs Up

____________________
'84 TS50X, '91 TZR125, '89 CBR400RR, '91 VFR400R NC30, '98 R1
"Hey copernicus! Why don't you navigate yourself to the back of the line with your feet and stand there with your shit."
BCF Eastern members map here ---> g.co/maps/2tm8b PM me to be added to it!

shadowbiker · Traffic Copper Joined: 14 Oct 2009 Karma :

hmmmnz · Super Spammer Joined: 22 Aug 2006 Karma :

your dreaming if you think you could get a 180cc kit for that bike,
that would be a 68mm bore, 18mm bigger than standard
your bottom end doesnt have the displacement to be able to shift the amount of fuel around required to get the bike running,

you could use a gp125 barrel and piston, as its the same stroke as the 100,
being a rotary valve, the potential for tuning is great,
all the gp 2 strokes used the system,
i currently own 3 rotary valve bikes, and out of a 125 with the right port timings and cut out on the rotary valve you could get 25-30 hp
with the standard port timing, and just mucking around with the rotary valve you could get 20hp with out too much trouble,

do some reading on rotary valves before you do anything,
i have a good bridgestone race manual that has some good tips in it (bridgestone (the tyre guys) used to make rotary valve bikes in the 70's and won loads of races)
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stevo as b4 · World Chat Champion Joined: 17 Jul 2003 Karma :

Yeah it does seem that some rotary valved bikes seem to be very tunable and make alot of power. I once heard of and saw a dyno chart for a Kawasaki AR125 that was making 30bhp at the rear wheel at only about 10.2k rpm. Apparently the rotary plus reed valve induction system made it really tractable too, and it would pull really well from about 7500-11000rpm.

Would love a 30bhp+ AR125! Laughing

hmmmnz · Super Spammer Joined: 22 Aug 2006 Karma :

the standard kawasaki kx125a1 from 1972 (father to the ar and kh bikes) produced 25hp at 9000rpm they were getting well into the mid 30's on the race models
the bridgestones 100 was getting almost 20hp in the late 60's on lightly modified bikes

add water cooling and you can get a pant load,
its not unheard of for the race rotary valve 125 bikes to be getting 50hp
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I kick arse for the lord
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smegballs · World Chat Champion Joined: 28 Oct 2007 Karma :

What is the advantage of rotary over reeds?

Personally I like the rotary's better but seeing as reeds can give a whole 360 degrees of inlet timing surely its hard to beat that?

hmmmnz · Super Spammer Joined: 22 Aug 2006 Karma :

smegballs · World Chat Champion Joined: 28 Oct 2007 Karma :

shadowbiker · Traffic Copper Joined: 14 Oct 2009 Karma :

i had compleatly forgot to update this ! Sad

well update

gp100 has had a overhaul everything works
and its now ready for it phase of ratting